From 1fabde7ab11cb7c04dfc8f08b71f04abb9217d48 Mon Sep 17 00:00:00 2001 From: Dale Rahn Date: Mon, 9 Feb 2004 21:09:32 +0000 Subject: Enable lazy binding on arm: _dl_bind_start inspired by netbsd. changed a define to LD_ALLOW_WRITABLE_TEXT, should this be allowed? remove plt protect code, arm has a text PLT. relocate the got entries associated with the plt. perform got protect/unprotect for lazy binding updates. --- libexec/ld.so/arm/rtld_machine.c | 93 +++++++++++++++++++++------------------- 1 file changed, 50 insertions(+), 43 deletions(-) (limited to 'libexec/ld.so/arm/rtld_machine.c') diff --git a/libexec/ld.so/arm/rtld_machine.c b/libexec/ld.so/arm/rtld_machine.c index 922e5046bec..020dbab60a5 100644 --- a/libexec/ld.so/arm/rtld_machine.c +++ b/libexec/ld.so/arm/rtld_machine.c @@ -1,4 +1,4 @@ -/* $OpenBSD: rtld_machine.c,v 1.2 2004/02/09 02:33:48 drahn Exp $ */ +/* $OpenBSD: rtld_machine.c,v 1.3 2004/02/09 21:09:31 drahn Exp $ */ /* * Copyright (c) 2004 Dale Rahn @@ -167,7 +167,9 @@ _dl_bcopy(const void *src, void *dest, int size) void _dl_reloc_plt(Elf_Word *where, Elf_Addr value, Elf_Rel *rel); -#define LD_PROTECT_TEXT +/* +#define LD_ALLOW_WRITEABLE_TEXT +*/ int _dl_md_reloc(elf_object_t *object, int rel, int relsz) { @@ -176,7 +178,7 @@ _dl_md_reloc(elf_object_t *object, int rel, int relsz) long fails = 0; Elf_Addr loff; Elf_Rel *rels; -#ifndef LD_PROTECT_TEXT +#ifdef LD_ALLOW_WRITEABLE_TEXT struct load_list *llist; #endif @@ -187,12 +189,14 @@ _dl_md_reloc(elf_object_t *object, int rel, int relsz) if (rels == NULL) return(0); -#ifndef LD_PROTECT_TEXT +#ifdef LD_ALLOW_WRITEABLE_TEXT /* * unprotect some segments if we need it. */ if ((rel == DT_REL || rel == DT_RELA)) { - for (llist = object->load_list; llist != NULL; llist = llist->next) { + for (llist = object->load_list; + llist != NULL; + llist = llist->next) { if (!(llist->prot & PROT_WRITE)) _dl_mprotect(llist->start, llist->size, llist->prot|PROT_WRITE); @@ -318,16 +322,18 @@ resolve_failed: } } -#ifndef LD_PROTECT_TEXT +#ifdef LD_ALLOW_WRITEABLE_TEXT /* reprotect the unprotected segments */ if ((rel == DT_REL || rel == DT_RELA)) { - for (llist = object->load_list; llist != NULL; llist = llist->next) { + for (llist = object->load_list; + llist != NULL; + llist = llist->next) { if (!(llist->prot & PROT_WRITE)) _dl_mprotect(llist->start, llist->size, llist->prot); } } - #endif +#endif return (fails); } @@ -340,13 +346,11 @@ resolve_failed: void _dl_md_reloc_got(elf_object_t *object, int lazy) { -#define DISABLE_LAZY -#ifndef DISABLE_LAZY Elf_Addr *pltgot = (Elf_Addr *)object->Dyn.info[DT_PLTGOT]; -#endif Elf_Addr ooff; - Elf_Addr plt_addr; const Elf_Sym *this; + int i, num; + Elf_Rel *rel; if (object->Dyn.info[DT_PLTREL] != DT_REL) return; @@ -365,13 +369,7 @@ _dl_md_reloc_got(elf_object_t *object, int lazy) if (this != NULL) object->got_size = ooff + this->st_value - object->got_addr; - plt_addr = 0; - object->plt_size = 0; - this = NULL; - ooff = _dl_find_symbol("__plt_start", object, &this, - SYM_SEARCH_SELF|SYM_NOWARNNOTFOUND|SYM_PLT, 0, object); - if (this != NULL) - plt_addr = ooff + this->st_value; + object->plt_size = 0; /* Text PLT on ARM */ if (object->got_addr == NULL) object->got_start = NULL; @@ -380,29 +378,23 @@ _dl_md_reloc_got(elf_object_t *object, int lazy) object->got_size += object->got_addr - object->got_start; object->got_size = ELF_ROUND(object->got_size, _dl_pagesz); } -#if 1 object->plt_start = NULL; -#else - if (plt_addr == NULL) - object->plt_start = NULL; - else { - object->plt_start = ELF_TRUNC(plt_addr, _dl_pagesz); - object->plt_size += plt_addr - object->plt_start; - object->plt_size = ELF_ROUND(object->plt_size, _dl_pagesz); - } -#endif -#define DISABLE_LAZY -#ifndef DISABLE_LAZY if (!lazy) { -#endif _dl_md_reloc(object, DT_JMPREL, DT_PLTRELSZ); -#ifndef DISABLE_LAZY } else { + rel = (Elf_Rel *)(object->Dyn.info[DT_JMPREL]); + num = (object->Dyn.info[DT_PLTRELSZ]); + + for (i = 0; i < num/sizeof(Elf_Rel); i++, rel++) { + Elf_Addr *where; + where = (Elf_Addr *)(rel->r_offset + object->load_offs); + *where += object->load_offs; + } + pltgot[1] = (Elf_Addr)object; pltgot[2] = (Elf_Addr)_dl_bind_start; } -#endif if (object->got_size != 0) _dl_mprotect((void*)object->got_addr, object->got_size, PROT_READ); @@ -412,17 +404,19 @@ _dl_md_reloc_got(elf_object_t *object, int lazy) } Elf_Addr -_dl_bind(elf_object_t *object, int reloff) +_dl_bind(elf_object_t *object, int relidx) { + Elf_Rel *rel; + Elf_Word *addr; const Elf_Sym *sym, *this; - Elf_Addr *r_addr, ooff, newval; const char *symn; - Elf_Rel *rels; + Elf_Addr ooff, newval; + sigset_t omask, nmask; - rels = ((Elf_Rel *)object->Dyn.info[DT_JMPREL]) + (reloff>>2); + rel = ((Elf_Rel *)object->Dyn.info[DT_JMPREL]) + (relidx); sym = object->dyn.symtab; - sym += ELF_R_SYM(rels->r_info); + sym += ELF_R_SYM(rel->r_info); symn = object->dyn.strtab + sym->st_name; ooff = _dl_find_symbol(symn, _dl_objects, &this, @@ -432,12 +426,25 @@ _dl_bind(elf_object_t *object, int reloff) *((int *)0) = 0; /* XXX */ } - r_addr = (Elf_Addr *)(object->load_offs + rels->r_offset); + addr = (Elf_Addr *)(object->load_offs + rel->r_offset); newval = ooff + this->st_value; - if (*r_addr != newval) - *r_addr = newval; + /* if GOT is protected, allow the write */ + if (object->got_size != 0) { + sigfillset(&nmask); + _dl_sigprocmask(SIG_BLOCK, &nmask, &omask); + _dl_mprotect((void*)object->got_start, object->got_size, + PROT_READ|PROT_WRITE); + } + + if (*addr != newval) + *addr = newval; + /* put the GOT back to RO */ + if (object->got_size != 0) { + _dl_mprotect((void*)object->got_start, object->got_size, + PROT_READ); + _dl_sigprocmask(SIG_SETMASK, &omask, NULL); + } return newval; } - -- cgit v1.2.3